Motor vehicle trailer



4 sheets-sheet i /NVENTOR DAVID o. ARI-:HART

D. D. AREHART MOTOR VEHICLE TRAILER Filed Oct. 19, 1936 Oct. 25, 1938.

BY 2mm MMM A Tron/yay s oct. 25, 1938.

D. D. AREHART MOTOR VEHICLE TRAILER` 4 sheets-sheet 2 Filed Oct. 19, 1936 /NVENTOR DAVID o. ARE HART A TTORNE YS Oct. 25, 1938. D. D. AREHART MOTOR VEHICLE '.1?RAII.\`E}Rl 4 sheets-sheet 3 Filed Oct. 19, 1956' A .4 F rlll- FIG.|O.

A TTORNE Y s Ej/ www, www mA.

Oct. 25, 1938. D. D. AREHART MOTOR VEHICLE TRAILER 4 Sheets-Shet 4 INVENTOR DAVID D. AREHART Elim-#HMM ATTORNEYS Filed Oct. 19, 1936 Patented Oct. 25, 1938 PATENT 'oi-Fics 2,134,351 Moron VEHICLE TRAILER David D. Arehart, Flint, Mich., assignor to Palace Travel Coach Corporation, Flint, Mich., a corporation of Michigan Application October 19, 1936, Serial No. 106,475

9 claims.

The invention relates to motor vehicle trailers and has more particular reference to constructions normally supported' on more than two Wheels, such for instance as three wheels.

' 5 Among the objects of the invention are: first, to

obtain easy riding qualities; second, to improve the steering of the trailer so that it will more accurately follow the path of the tractor; third,

to facilitate backing wherever this is necessary. With these and other objects in view, the invention consists in the construction as hereinafterA set forth.

In the drawings:

Figure 1 is a. side elevation showing a portion of a tractor to which my improved trailer is coupled;

Figure 2 is a plan viewthereof;

Figure 3 is a vertical section showing the draft connection for the trailer and the third wheel;

Figure 4 is a plan View of Figure 3;

Figure 5 is a view similar to Figure 3 showing a modified construction; l

Figure 6 is a vertical section showing the manner of attaching the king-pin;

Figure 7 is a view similar to Figure 4 showing a modied construction;

Figure 8 is a view similar to Figures 3 and 5 showing still another modification;

Figure 9 is a section on line 9-9 of Figure 8;

Figure 10 is a plan view of Figure 11;

Figure 11 is a vertical longitudinal section illustrating a. different form of draft rigging;

Figure 12 is'a section on line IZ-IZ of Figure 10:

Figure 13 is a. section on line I3-l3 of Figure 10; v

Figure 14 is a view similar to Figure 8 but showing the draft rigging of Figures 10 and 11;

Figure 15 is a plan view of another modification of the type illustrated in Figure 10;

Figure 16 is a cross section on line Iii-I6 of Figure 15. I

Automobile trailers when in transit are usually supported on only two wheels journaled on a single axle which is arranged adjacent to the center of gravity, the draft rigging being d epended upon for stability. Such a construction cannot have as easy riding qualities as one supported on a plurality of axles with spaced spring supports for the body of the car. A With my improved construction a third wheel is provided, preferably at the front of the trailer, and this is so connected with the draft rigging as to be automatically turned in correspondence with any change in direction of the tractor. As shown (ci. 28o-33.5)

A ally from the head G' at the base of said'kingto the head G'.

and as preferably constructed, this thirdy wheel is of the caster type its swivel connection with the trailer body being in advance of its axis of rotation. This facilitates the steering of the trailer when it is traveling forward, but vrenders 5 backing more vdlicult. I have, therefore, devised a construction which while using a caster wheel can be readily steered when driven backward. This is accomplished through the construction of the draft rigging and its combi- 10 nationwith the caster wheel as hereinafter described. A further feature of my improvement is the spring suspension of the trailer body upon the caster wheel which cushions vertical shocks without. interference with freedom for lateral 15 turning about the swivel axis.

In detaiLArepresents the tractor which may be an automobile or any other type of vehicle.

B is the trailer body which in its rear portion is supported upon an axle C and a'pair of ground 2u wheelsD, any suitable type of spring suspension (not shown) being interposed between the axle. and trailer body. E is the third wheel which is beneath the forward portion of the trailerbody and is connected thereto through the forwardly extending arm F and king-pin G. To permit of relative vertical movement ofthe wheel D and body B, the arm F is connected to the king-pin by a horizontal pivot pin H which projects later- 30 pin. There is also a spring suspension which as shown in Figures3, 5 and'll is formed `of leaf springs I clipped or otherwise secured at I4 The outer end of this spring is connected to the arm F by suitable means such as a shackle I2, Figures 3 and 11, or the bearing I3, Figure 5, which slidably engages one leaf on the spring. The king-pin G is swiveled in a bearing G2 which through the ange G3 and bolts G4 is rigidly securedto the sills J forsupporting the trailer body. These sills, as shown in Figures 1 and 2, have parallel portions J extending the greater part of the length of the body and oblique portions J2 extending towards each other and having their forward ends connected to the bearing G slightly in advance of the body B.

The draft rigging between the tractor and trailer comprises a draft bar K, the forward end of which is pivotally attached at K to a suitable bracket member K2 secured in any suitable manner to the tractor. Thepivotalconnection K' is preferably a universal joint permitting of the swinging of said draft bar in both vertical and horizontal planes. Thus as shown the bracket K? has mounted thereon a post member K3 havpivotal connection K' ing -a spherical upper end K4 for engaging a .spherical socket in the draft bar. The rear end of the'draft bar is connected by a pivot pin KI5 to the head G', this permitting of relative vertical oscillation 'of the bar K and arm F, but holding these members in alignment in a horizontal plane. Thus anychange in direction of movement of the tractor will cause a lateral movement of the draft bar K and arm F valigned therewith 4which will turn the wheel E about a vertical axis intersecting its axis of rotation, This will also move the king-pin G and bearing G2 laterally but not to the same extent, inasmuch as the pin isLin rear of the draft bar. Where, as shown, the pivotal connection K is in rear of the bumper L, it Qis located a considerable distance in back of the tractor rear axle. Thus where the tractor is turned in one direction the will-be swung in the opposite direction which will turn the plane of lthe wheel E so that the forward end of the trailer will be directed outward or opposite to the direction of turning of the tractor. Also, the lateral movement of the king-pin G will turn the longitudinal axis of the body slightly outward but to a lesser extent. This will assist in causing the trailer to follow the path of the tractor instead of cutting the corner.

The construction as thus far described will operate satisfactorily as long as the movement is in a forward direction. If, however, the tractor is backed, then there will be a tendency for the draft bar K to swing about the pivotal connection K' permitting the wheel E to travel either one side` or the other of the desired direction. This tendency I have avoided by the following construction:

On each side of the draft bar K are arranged diagonally extending draft connections M which at their forward ends are suitably attached to the tractor as to brackets L' on the bumper L, while at their rear ends they are connected to the head G. 'I'hese draft connections may be formed buckle M2 for properly adjusting the length. 'Ihe tension of the spring M' is sufdcient to normally hold the draft bar K in alignment with A the longitudinal axis of the tractor and as long as .the tractor is traveling in a straight line it will maintain this position. When, however, the tractor is turned the pivotal connection K will be swung outward as previously described, while the wheel E because of itsground contact will be held from lateral movement. This will change the angle of the draft bar and arm F which necessitates an elongation of the outer diagonal draft connection M permitted by the spring M' and thus these members .M will in no way interfere with the operation when the tractor is moving in a forward direction. On the other hand, when the tractor is backed, then tension of the springs M will initially hold the draft bar K in alignment with the longitudinal axis of the tractor and will counteract any tendency in this member to swing about the pivotal connection -extending rearward from the Aaxis of the king pin G. The rear end of this arm O is pivotally connected to lever members vO and O2 which at their outer ends have mounted thereon grooved rollersiiiigin traveling contact with flanges J3 on the inclined portions J2 of-.the sill members J. The lever members O and O2 have also connected to their outer ends the links O4 and O5 which extend to the tractor and are universally pivotally attached thereto, as indicated at Of. As shown, this attachment is to the outer ends of a cross-arm O7 which is mounted on the bracket K2 to which the draft bar N is universally pivoted. The arrangement is such that whenever there is a change in the direction of movement of the tractor causing a lateral andangular movement of the bracket K2 and arm O?, this will draw one of thelever arms O', 02 forward on the sill member J2 and will force the other lever arm backward on its sill member. This in ,turn will permit the swinging of the crank arm O and the angular movement of the arm F with respect to the draft arm N and longitudinal axis of the tractor body, so that the trailer will be steered in the vsame manner as with the construction previously described. arm F is held from swinging about the axis of the king-pin G as this cannot occur without a relative movement of the arms O and O2 which are held from such movement by the tension of the links O4 and O5. If, however, the backing is not in a straight line, then the swinging of the arm F and king-pinlis permitted to the extent required. l i

In place of the spring suspension illustrated in Figures 3, 5 and 11, I may employ as a modification the construction shown in Figures 8 and 14. In this the arm F is bent downward from its point of attachment to the pin H, as indicated at F', and then has a substantially horizontal portion F2. This is arranged beneath a portion vG5 of the head G' and between these portions is arranged a coil spring P. Thus downward movement of said head is yieldably resisted hv this spring.

In each of the constructions shown in Figures 3, 5 and l1, the spring is in the form of a cantilever arm which is rigidly attached to the head G' and at its rear end is coupled to thearm F. In all of the constructions the reaction of the spring is carried into the king-pin and from the latter into the bearing G2 which is rigidly attached to the converging sill members J2. This construction permits of using a relatively long bearing and king-pin, thereby reducing the magnitude of the radial thrust transmitted from the pin to the bearing.

Figure 15 shows another modification of a somewhat similar type to that illustrated in Figure 10. In this the angularity of the caster 4wheel with respect to the trailer is positively determined by cams Q and Q' which slidably engage channels in the sill members J2 and are actuated by links connected to the tractor. As'

In straight backing the' which is attached to the king-pin. Cross-links Qs are pivotally attached to the members Q and Q and extend forward therefrom through the ends of the channels with their forward ends pivotally Aattached to arms Q8 and Q9 rigid with the tractor and on opposite sides of the draft bar connecting the same to the trailer. Thus where there is any change in direction of the tractor caster wheel.

one or the other of the cams Q and Q will be moved forward and through engagement with the roller Q4 will swing the crank arm Q5, thereby correspondingly changing the angle of the Thus this construction as Well as the construction shown in Figure l0 will positively determine the angular'. relation of the caster wheel to the'trailer through the operation of non-yielding elements connecting the same with the tractor.

What I claim as my invention is:

1. The combination with a trailer, of a caster wheel forming a support therefor and including a king-pin pivotally engaging said trailer having a head at its lower end, an arm extending rearward from said king-pin, a horizontal pivotal connection between the forward end of said arm and said head permitting swinging movement in a vertical plane, a wheel supporting the rear end of said arm, and resilient means interposed between said head and arm for yieldably supporting the load; and a draft connection pivotally attached to said head to permit swinging -in a vertical plane while preventing relative movement in a horizontal plane.

2. The combination with a trailer, of a .caster wheel forming a support ltherefor and including a king-pin pivotally engaging said trailer having a head at its lower end, an arm extending rear- `ward from said king-pin, a horizontal pivotal connection between the forward end of said arm and said head permitting swinging movement in a vertical plane, a wheel supporting the rear end of said arm, and resilient means interposed between said head and arm for yieldably supporting the load; a draft connection pivotally at` tached to said head to permit swinging in a vertical plane while preventing lrelative movement in a horizontal plane, a tractor to which the forward end of said draft connection is universally pivoted, and resilient means for yieldably holdingsaid draft connection in line with the direction of movement of said tractor.

3. The combination with a trailer, of a caster Wheel forming a support therefor-and including a king-pin pivotally engaging saidtrailer having a. head at its lower end, an arm extending rearward from said king-pin, a horizontal pivotal connection between the forward end of said arm and said head permitting swinging movement in a vertical plane, a wheel supporting the rear end of said arm, and resilient means interposed between said head and arm for yieldably supportlng the load; a draft connection pivotally attached to said headto permit swinging in a vertical plane while preventing relative movement in a horizontal plane, a tractor to which the 'forward end of saiddraft connection is universally pivoted, and means for yieldably holding said draft connection in line with the direction of movement of said tractor comprising resilient -end of the trailer, a king-pin bearing mounted on the forward ends of said sills and extending upward therefrom, a king-pin engaging said bearing having ahead at its lower end, an arm extending rearward from said king-pin pivotally attached to said head to permit swinging in a vertical plane, a wheel supporting the rear' end of said arm, and resilient means interposed between said' .head and arm for yiel'dably supporting the load.

5. The combination with a trailer, of supporting sills therefor having converging forwardly extending portions extending beyond the forward end of the trailer, a king-pin bearing mounted on the forward ends of said sills and extending upward therefrom, a king-pin engaging said bearing having a head at its lower end, an arm extending rearward from said king-pin 4pivotally attached to said head to permit swinging in a vertical planefavwheel supporting the rear end of said arm, resilient means interposed between said head and arm for yieldably supporting the load, and a draft connection pivotally attached to said head'to permit swinging in a vertical plane while main-tained in fixed relation thereto in a horizontal plane.

6. The combination with a trailer, of supporting sills therefor having converging forwardly extending portions projecting beyond the forward end of the trailer body, a king-pin bearing mounted upon the projecting end'pprtions of said sills and extending upward therefrom, a king-pin engaging said bearing and having a head at its lower end, an arm.. extending rearward from said king-pin and pivotally attached to saidy head to permit swinging in a vertical plane, a wheel sup-A porting the rear end of said arm, and a cantilever spring secured to said head to project rearward therefrom and having its rear end attached to said arm. l

7. Thecombination with a trailer, of supporting sills therefor having converging forwardly exv tending portions, a caster wheel forming a support for said trailer and including a king-pin bearing mounted at the forward ends of said sills, a king-pin engaging said bearing, an arm extending rearward from said king-pin and a wheel supporting the rear end of said arm, a tractor, a

draft connection for said trailer pivotally. at-

in one direction or the other when moved forwardv from normal position by the draft of their respective links.

8. The combination with a trailer, of supporting sills therefor having converging forwardly extending portions, a caster wheel forming a support for said trailer and including a king-pin bearing mounted at the'forward ends of said sills, a king-pin engaging said bearing, an arm extending rearward from said king-pin and a wheel supporting the rear. end of said arm, a tractor, a draft connection vfor said trailer pivotally attached to said tractor, and means for ypositively "IOA determining the angular relation of said` caster v7 wheel to said trailer by the angular relation' vof said draft connection to said tractor comprising a crank arm extending rearward from said kingpin, a pair of members having traveling engage'- ment with said converging sill members, links connecting said traveling members withsaid tractor on opposite sides of the pivotal attachment to said draft connection, and levers connecting the respective traveling members with the rear end of said crank arm.

9. The combination with a trailer, of supporting sills therefor having converging forwardly extending portions, a caster wheel forming a support for said trailer and including a king-pin bearing mounted at the forward ends of said sills, a king-pin engaging said bearing, an arm ex- 'tor on opposite sides of the pivotal attachment to said draft connection, a roller on the rear end of said crank arm and cam t'racks on the respective traveling members for engaging said roller.

DAVID D. AREHART. 

